dac operation

Operations for 13IDD-DAC setup
                       13-ID-D DAC Angle Dispersive Diffraction
                   13-ID-D Laser Heating System
                   Frequently asked questions

Generated on August 20, 2005 by Guoyin Shen
Last modified -------- by --------

A. Operations of 13-ID-D angle dispersive diffraction with DAC

A.1    Control interfaces
            MEDM
            IDL
            Fit2D
A.2    Operations of ADX
            X-ray beam
            Detector calibration
            Mounting DAC
A.3    Scan
            Method 1 (a simple one for scanning one or two motors, using IDL widget)
            Method 2 (a scan procedure in MEDM, can be used for any named parameter variable 'PV' name)
A.4    Area Detectors
A.5    Troubleshooting
           No x-ray beam

B. Operations of 13-ID-D Laser Heating System

        Pre-alignment of laser heating path with x-ray
            Getting ready
            Mounting DAC
            Alignment of laser heating optics with x-ray
            Turning on lasers
            Adjusting the laser power
            Feed back system
            Data logger
            Winspec/32 setup
            Winvew/32 setup
            Temperature measurement software
            Monitor setup

A. 1. Control interfaces

MEDM

Click the shortcut MEDM at the desk top, you will have a MEDM window:

Click IDD Experiments > 13 IDD DAC , you will have the main control window for DAC experiments at 13ID-D.

IDL

Click the shortcut IDL 6.0 at the desk top, you will have an IDL window:

Under File>Preferences>Path, make sure the following setup:

Under File>Preferences>Startup, setup the desired working directory:

Click OK.

Fit2D

Click the shortcut Fit2D at the desktop, you will have a window:

Click "I ACCEPT", then make sure to put the right dimensions of arrays.

Fit2D is a well documented software. You may get instructions from: http://www.esrf.fr/computing/scientific/FIT2D/

A. 2. Operations of ADX 13IDD-DAC

X-ray beam position

X-ray beam is pre-aligned to the rotation center of the sample stage. Therefore, we will start with checking the rotation center first. Then we will make sure that the x-ray beam is focused at the center. This process is made with the help of a cross hair.

    · Move stages X, Y, S1, S2, and Omega all to 0 (zero). For Omega stage, you may need an IDL window for rotation. In the IDL command line, type "rotate_omega, degree". Note that the degree number is always relative, with positive number in clockwise direction if you look down.
    · Put a cross hair on the DAC setup.
    · Move microscope "IN" in the main control window. You should see the cross in the monitor (see monitor setup). If you do not see the cross hair, contact beam-line staff.
    · Rotate Omega -180 degrees ("rotate_omega, -180, psw=1" in IDL). The cross hair should stay at the center. If not, contact beam-line staff.
    · Move the microscope away.
    · Rotate Omega 90 degrees ("rotate_omega, 90" in IDL).
    · Scan clean-up slits first (see Scan for setup).
    · Scan the cross hair. The cross hair should be close to the zero positions of all stages within 20 um. If not, contact beam-line staff.

Detector calibration

Detector calibration is made by a couple of standard materials (CeO2, Si). Then by using the build-in features in Fit2D, the tilt and sample-detector distance can be determined. The x-ray energy is calibrated independently, by scanning an absorption edge of a particular element, which is usually done by beam-line staff. Contact beam-line staff for more information (accuracy, etc) about the x-ray energy.

    · Move the clean-up slits "OUT".
    · Rotate Omega to 0 (zero) position (use IDL).
    · Put the holder with CeO2 standard. Under IDL command line, type "item, 'ceo2' ".
    · Move microscope "IN". You should see the CeO2 standard. Small adjustment maybe needed.
    · Move microscope "OUT".
    · Rotate Omega -90 degrees.
    · Move the clean-up slits "IN".
    · Scan clean-up slits. (refer to Scan)
    · Get detector ready (refer to Detectors). If IP is used. Erase the IP before taking the standard exposure. Typically 1 second is enough for CeO2.
    · Use Fit2D for imaging loading and detector calibration.

Mounting DAC

Now the system is ready for mounting your sample. For checking starting materials or quenched samples, there are special holders for that. Contact beam-line staff for those holders. The following is for DAC sample setup. Please note: if you are a new user, always discuss with beam line staff first for appropriate holders.

Move clean-up slits "OUT".

Make sure X-stage is at 0 (zero). Move Omega to 0 (zero).

Put DAC on the sample stage. Connect water cooling pipes if needed.

Move microscope "IN", and click "zoom out".

Use only stages S1, S2, and Y to control positions and focus. Do not use the stage X for finding sample.

Click microscope "zoom in" for fine adjustment.

Make diamond thickness correction
----thickness of diamond x 0.587 = the amount of correction
----move the DAC toward the microscope by that correction amount

If the DAC holder is big, take the DAC off the sample stage before rotating Omega.

Rotate Omega stage 90 degree relatively. Make sure the right side of DAC faces toward downstream. (For the symmetrical cell, put the piston side toward downstream).

Click Photodiode "IN"; scan sample position by using the photodiode.

The DAC sample is ready for taking diffraction.

A. 3 Scan

Method One:

open an IDL window (refer to IDL)
Under command line, type widget_scan

Description:

scan type: scaler for scaler detectors (e.g., photodiode); roi for multi-channel detectors (e.g., MCA)
scan dim: 1-D; 2-D
# motors: up to 2 motors
Count time: e.g., 0.3 s for photodiode; 1 or longer for roi
Total time: the calculated time for the whole scan
Motor name: motor name can be got by clicking the middle button on the motor in MEDM window
or check the list posted in the beamline
Scaler PVname put 13IDD:scaler1 for photodiode
# scaler: change to 3
Plot: click the plot for time off
MCAPVname: For roi scan, put detector name 13IDD:aim_adc1 (for ROI change each time, hit return in this box to refresh)
Back. width: change to -1 (No background correction)
For ROI scan, click the plot for photodiode off.
Timing mode: Live
Scan filename: put the proper name. If ending with a number, the increment scan will be saved.

In the same IDL window, type scan_view.

In the widget window, click Start scan to start. After scan, all motors will move back to the initial positions.
The scan data will be displayed in the SCAN_VIEW window.
Use Position (one click) or Center (center of two clicks) to get desired positions; use MOVE to move the motor to that position.
You may abort scan by clicking the Abort scan at any time. All motors will move back to the initial positions.

Method Two

Used for scanning any positioners (a motor, a compound motor, or anything that has a PV name and can be controlled to "change") while watching any detectors (time, intensity of the photo diode, ROIs in the MCA, or anything that can be measured).

Scan parameter window

In the main DAC window, click FULL IDD CONTROL (lower-left corner), go to SCAN > scan2 (scan1 is usually used by LVP people)

    · For single motor scan, just fill in the PV names under positioners.
    · For multiple motor scan, click the button "Positioners", which allows you to enter up to four positioners for each scan.
    · PV names under Detector trigger are used for trigging detectors. The example shown is for scaler1 in 13ID-D and MARCCD.
    · PV names under Detectors are those that you want to be recorded for a scan. Put the desired names there. Data can be plotted by clicking the numbers of the corresponding detectors .

Area detectors

MAR-IP3450

The MAR-IP is controlled by a computer named "mini"
To start MAR-IP control interface, just type "MAR345" in a terminal window.

MAR-CCD

Currently, a MAR-CCD from APS detector pool is used. The detector comes with a computer.
MAR-CCD can be controlled by EPICS. The setup is done by beam-line staff.

Fuji BAS2500

Fuji BAS2500 is an off-line reader. Two sizes of imaging plate are available. One is 20x25 cm^2; the other is 20x40 cm^2.

Troubleshooting

no x-ray beam

       · Is the main shutter open? If yes, check the window at the lower-right corner of the DAC window. If current reading is 0(zero), contact beam-line staff.

        · If Current reading changes over time as shown below, this means that the Setpoint is a little too high for the feedback to keep the top number. Reset the Setpoint number (5% below the maximum).

        · If you have a good reading from Current, but no x-ray beam from photodiode, then check the following:
                · Is the table-top shutter OPEN?
                · Is clean-up slit at the right position?
                · Is the photodiode IN?
                · If yes to all above, but still no beam, contact beam-line staff.

Operations of the 13-ID-D Laser Heating System

Alignment of laser heating path with x-ray

This procedure is done normally before experiment. Only do this when problems observed or to confirm the alignment.

Put a cross-hair at the rotating center (refer to x-ray beam position for step-by-step procedures).
Scan the cross hair with motors S1 and Y. Check if the x-ray position matches the rotating center.
Move both Up-stream and Down-stream mirrors IN; Observe the cross hair by the two laser heating microscopes.
The upstream image is controlled by WinView. Refer to WinView32 for operation. The monitors for these two microscopes are located on shelves in the control area. The cross mark on the monitor is aligned to the spectrometer for the temperature measurement. So do not erase the cross mark.
Adjust focus when necessary to reach the image of the cross-hair. Usually for the cross-hair, these numbers are close to 0 (zero).
You may align the cross-hair to the cross mark on monitors by adjusting the carbon mirrors.
Replace the cross hair by a Pt-foil; In an IDL window, type: item, 'Pt'; find the Pt foil.
Turn on He-Ne laser. The He-Ne laser is located behind the first mirror receiving the laser output.
Observe if the red He-Ne laser can be seen on screen. If not, stop and contact beam-line staff.
Move sample stages to find a reference point for fine tune alignment of both sides (by carbon mirrors only).
Turn one YLF laser on, refer to Turning on lasers.
Increase laser power until you see glows, refer to Adjusting the laser power.
The heating spot should be at the cross mark on the monitors. If it is far away from the cross mark, contact beam-line staff. If it is close within 10 um, adjust the glow spot to the cross mark on screen by upstream/downstream laser mirrors. (!!!Not the carbon-mirrors!!!). This adjustment can be done only when you use the Pt foil. The adjustment procedure should not be applied for DAC samples unless you are absolutely sure.
Turn on the other YLF laser, check the alignment.

Getting ready

Mounting DAC

Move two laser heating microscopes OUT.
Refer to regular Mounting DAC.
Scan the DAC sample by x-ray; locate at approximate center of the sample chamber.
Move two laser microscope IN; turn on illuminating lights.
Adjust the focus (to negative directions) for having clear images
Adjust carbon mirrors to have both sides looking at the central area.

Alignment of laser heating optics with x-ray beam

Turn off the illuminating lights; move two splitters OUT.
Turn off the hutch room-light.
Access x-ray beam. You may see the x-ray beam in the two monitors. If weak, change the sensitivity under Winview.
Adjust the two carbon mirrors if the x-ray beam images are clear. These images have to be adjusted to the centers of the cross marks.
Now the x-ray beam is aligned with the temperature measurement system

Turning on lasers

You have to be a qualified user before working with YLF lasers.
For the first time user, contact beam-line staff for training. You need to read SOP posted on the door of 13ID-D and sign the user sheet.

Lasers

Get keys from CARS's staff.
Turn on the key switch by 90 degrees.
Press green button (hold for 2-3 seconds) for cooling water. Make sure the water is circulating.
Press Lamp On button (hold for 2-3 seconds).
Adjust the current control knob to 33 A (the working current).

Interlock (user mode only)

Press Interlock located outside the hutch.
Turn on the key switch by 90 degrees.
Now the laser is accessible by just pressing the shutter on the control box. Before turning on the shutter, make sure you are familiar with the way of adjusting the laser power (see next) and that the two table-top shutters are closed.

Adjusting the laser power

The laser power of both lasers are controlled by waveplates which are controlled under EPICS in the main DAC window (Upper-center region). The number reflects an angle in degrees, with 0 at the minimum power and 45 at the maximum.
The proportions to upstream/downstream can be changed (or balanced) by controlling the balance-waveplate. The number of 0 means an even (50/50) distribution. Positive (negative) number is more to the upstream (downstream) side.

Feed back system

The feed back system monitors the thermal radiation from the heated spot at the downstream side and feeds back to the waveplate-controlled power.

Turn on the high voltage for the PMT. From the main MEDM window, go to Full IDD control > MCA electronics > Canberra HVPS, set voltage to -500 V and turn on. Then increase to -750 V to -950 V, depending on the signal levels.

· From the main MEDM window, go to Laser control > Laser control slow. Set the PV names as shown.

· Go to More and click Plot control value:

· Read the Readback value, and put the Setpoint with a close value to the Readback.
· Then turn ON the Feadback.
· Change the Setpoint value for increase/decrease the sample temperature.

Epics Logger (data logger software)

The experimental parameters can be lively recorded by using a data logger program in IDL.

· In an open IDL window, type: epics_logger
· From File, you select the input data file and the output file. There is a file P:\dac_user\data_logger\laser_logger.dat for input data file. Using this file will record the time and date, the setpoint, the readback, the upstream temperature, the downstream temperature, and the photodiode output for the laser power. You may create your own data file for your needs. Basically any parameter variables (motor positions, slit width, ring current etc) can be recorded. Of course, an output file should be set for storing the data.
· Update time in the epics logger should be set (typically 1 sceond).

Winspec/32

Open Winspec/32 by follow: Start>All Program>Roper Scientific>Winspec32.
Go to Setup>hardware>controller camera.
Check/Set parameters as shown
Under Cleans/Skips menu
Check/Set parameters as shown
Click OK

Go to Acquisition>Experiment Setup

Use Data File to name the files to be saved.

-----The computer at upstream side is for upstream side temperature measurement

-----The computer at downstream side is for downstream side temperature measurement

-----Make sure to name files which can be recognized the side and other conditions. It is better to use the Auto Increment File Name option so that the files can be saved automatically.

The background file can be put into the Data Corrections.

Click OK to accept.
In WinSpec/32 window, from File, open a file made for wavelength calibration. The file is at C:\IDL\calib\wave_sp*_*.spe. sp1 and sp2 are for upstream and downstream, respectively.
From Calibration in WinSpec/32 window, check wavelength calibration.
Activate the Save as Default button, so that the spectra from now on will carry a right wavelength calibration.
Minimize Winspec/32 window.

Temperature Measurement

Temperature is measured by collecting the thermal radiation from a hot spot. The radiation signal is fitted to the Planck law and the fitting parameters give temperature values. The control is done by a GUI written in IDL. This GUI talks to Winspec32 and calculates temperatures. So file names have to be specified first in Winspec32. Refer to Winspec32 for the setup.

        · Open a new IDL window.
        · In the command line, type: spect

· Click Setup Parameters ..., it will show:

          · Make sure that Detector side and other parameters are correctly selected. Click Apply (or others as desired).
          · It is essential to load a Standard before a temperature calculation may be performed.
          · If the GUI freezes, go to the IDL window which opens the SpecT, and type "retall".
          · If EPICS control is set to "yes", then temperature measurement can be triggered by "Measure T" in the upper-left corner in the DAC main window. The calculated temperatures are also displayed in the main window.

Winview32

Winview is installed in the comuter "EXCURSIION".
Open Winview32 by follow: Start>All Program>Roper Scientific>Winspec32. Or double click the shortcut at the desktop.
Under Setup>Hardwares

Click OK. Winview is ready for taking data

Monitor Setup

There are four monitors in the 13ID-D, two outside the hutch and two inside. Those monitors can display video images from any source controlled by EPICS. Control buttons in the upper-left side in the main control window can be used for those operations.